Rotary drill head position measurement system

ABSTRACT

A blast hole drill machine ( 100 ) including a deck frame ( 102 ), and a mast ( 106 ) mounted on the deck frame ( 102 ) is provided. A feed cylinder ( 120 ) supported on the mast ( 106 ) and configured to move in proportion to movement of a rotary drill head ( 114 ) along the mast ( 106 ). A position magnet ( 202 ) is moveably disposed on the feed cylinder ( 120 ). A linear transducer ( 204 ) extends along the mast ( 106 ) and configured to detect a movement of the position magnet ( 202 ) indicative of a change in a position of the rotary drill head ( 114 ).

TECHNICAL FIELD

The present disclosure relates to a blast hole drill machine, and particularly to a rotary drill head position measurement system for the blast hole drill machine.

BACKGROUND

Systems for monitoring drilling operations allow drilling machines to operate semi-autonomously or autonomously. For example, various techniques to monitor a change in a linear position of a drill bit are known. These conventionally known techniques may use cables, strings, and/or rotary transducers to monitor the change in the linear position of the drill bit. However, due to rough and dirty working conditions of such drill machines are required to operate, these cables, strings and rotary transducers are extremely prone to wear and tear which further results in incorrect measurement of the change in the linear position of the drill bit.

SUMMARY

In one aspect, a blast hole drill machine is disclosed. The blast hole drill machine includes a deck frame, a mast mounted on the deck frame, and a feed cylinder supported on the mast and configured to move in proportion to movement of a rotary drill head along the mast. Further, a position magnet moveably disposed on the feed cylinder. A linear transducer extending along the mast and configured to detect a movement of the position magnet indicative of a change in a position of the rotary drill head.

In another aspect, a method of determining a rotary drill head position is disclosed. The method includes moving the position magnet corresponding to a movement of the rotary drill head and detecting a strain pulse using a magnetostrictive waveguide based on the movement of the position magnet. Method further includes generating an electrical signal based on the strain pulse indicative of a position of the position magnet.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates side elevation view of a blast hole drill machine;

FIG. 2 illustrates a schematic view of a cable feed system, according to an aspect of the present disclosure; and

FIG. 3 illustrates an exemplary method flow chart for determining a rotary drill head position in the blast hole drill machine.

DETAILED DESCRIPTION

The present disclosure relates to a system and a method for determining a rotary drill head position of the blast hole drill machine. FIG. 1 illustrates a side elevation view of an exemplary drilling machine such as a blast hole drill machine 100. The blast hole drill machine 100 may include a deck frame 102 supported on a transport mechanism such as crawler tracks 104. The blast hole drill machine 100 further includes a mast 106 mounted on the deck frame 102 and supported about a pivot 108. During a drilling operation, the blast hole drill machine 100 is supported on jacks 110. The blast hole drill machine 100 uses long straight sections of drill pipe 112 which are connected to a rotary drill head 114, to rotate a drill bit 116 and perform the drilling operation. The rotary drill head 114 is mounted on the mast 106 and is configured to travel up and down the mast 106 using a cable feed system 118.

FIG. 2 illustrates a schematic view of the cable feed system 118, according to an aspect of the present disclosure. In an embodiment, the cable feed system 118 includes a dual rod, single piston type hydraulic feed cylinder 120 having a cylinder body 122, a first piston rod 124, and a second piston rod 126. The first and the second piston rods 124, 126 attached to a common piston 128 (shown in dashed lines) slidably disposed within the cylinder body 122. The piston 128 defines an upper chamber 130 and a lower chamber 132 within the cylinder body 122. Further, the cable feed system 118 includes a pulley block 133 attached to the first piston rod 124, and a pullback cable 134 with one end attached to top of the rotary drill head 114. The pullback cable 134 is received over the pulley block 133 and a first pulley 136 mounted at the top of the mast 106 and where the other end of the pullback cable 134 is also anchored. Further, a pulldown cable 138 is fastened to bottom of the rotary drill head 114 at one end. The pulldown cable 138 loops under a second pulley 140 mounted at the bottom of the mast 106 and where the other end of the pulldown cable 138 is also anchored.

During the drilling operation, when a pulldown force is required, a pressurized hydraulic fluid is directed into the upper chamber 130 of the cylinder body 122 to force the second piston rod 126 out of the cylinder body 122 and, thereby pushes the cylinder body 122 upwards and thus lowering the rotary drill head 114. Alternatively, when a pullback force is required, the pressurized hydraulic fluid is directed into the lower chamber 132 of the cylinder body 122 to force the first piston rod 124 out of the cylinder body 122 and, thereby pushes the cylinder body 122 downward and thus raising the rotary drill head 114. The illustrated cable feed system 118 is merely exemplary and may vary to achieve similar functionality.

According to an aspect of the present disclosure, a rotary drill head position measurement system 200 is provided. The rotary drill head position measurement system 200 is configured to detect a position of the cylinder body 122 and determine a change in a position of the rotary drill head 112. In an embodiment, the rotary drill head position measurement system 200 may include a position magnet 202 moveably disposed on the cylinder body 122 of the feed cylinder 120. The position magnet 202 may be a permanent magnet and attached to the cylinder body 122 by any suitable means known in the art such as welding or using mechanical fasteners. The position magnet 202 is configured to move with the upward and downward movement of the cylinder body 122 of the feed cylinder 120 and in proportion to movement of the rotary drill head 114 of the blast hole drill machine 100, which travels approximately double the distance traveled by the feed cylinder 120. The rotary drill head position measurement system 200 further includes a linear transducer 204 extending along the mast 106 and configured to detect a change in a position of the position magnet 202 which is indicative of the change in the position of the rotary drill head 114. In an exemplary embodiment, the linear transducer 204 may output position information to an electric controller in either analog or digital format which is proportional to a change in a linear position of the drill bit 116 based on the change in a position of the rotary drill head 114 during the drilling operation.

In an exemplary embodiment, the linear transducer 204 may be a non-contacting type magnetostrictive position sensor including a magnetostrictive waveguide 206, hereinafter referred to as the waveguide 206. The waveguide 206 extends up to half a length of the mast 106. For example, the waveguide 206 extends from a top of the mast 106 up to a middle part of the mast 106. In an exemplary embodiment, the waveguide 206 may be a uniform diameter tube or a wire made from a magnetostrictive material such as iron, nickel, cobalt, and their alloys. In an exemplary embodiment, the waveguide 206 may be housed within a sensing tube such as a brass tube. The waveguide 206 may be secured to brackets (not shown) at both ends, where the bracket at one end is a coupling between the waveguide 206 and a biasing member that may apply appropriate tension to the waveguide 206 to maintain the physical straightness of the waveguide 206. As will be understood, the waveguide 206 may not be linear but may be curved in alternate embodiments to achieve similar results.

In an aspect of the present disclosure, the linear transducer 204 further includes a number of signal input wires connected to a first end 208 of the waveguide 206. The signal input wires are configured to introduce an electric current at one end of the waveguide 206. In an aspect of the present disclosure, while the position magnet 202 moves along with movement of the feed cylinder 120, there is a first magnetic field generated by the position magnet 202. Further, the signal input wires at the first end 208 of the waveguide 206 introduce an electric current pulse across the waveguide 206. In an aspect of the present disclosure, the waveguide 206, the brackets, the biasing member, and the brass tube are electrically conductive such that an electrical circuit is established between the terminals on the ends of the signal input wires. The introduced electric current generates a second magnetic field on the waveguide 206. Further, the first magnetic field of the position magnet 202 and the second magnetic field of the waveguide 206 may intersect at the position of the position magnet 202 within the mast 106. The intersection of the two magnetic fields may generate or introduce a mechanical strain pulse which travels at a pre-determined speed from its point of generation towards a second end 210 of the waveguide 206.

Furthermore, the mechanical strain pulse is received by a sensor element such as a piezoceramic element 212 operatively coupled at the second end 210 of the waveguide 206. In an aspect of the present disclosure, the piezoceramic element 212 may be a ceramic chip of a suitable dielectric material, such as lead zirconate titante. In an aspect of the present disclosure, the linear transducer 204 is configured to determine a time lapse between the introduction of the electric current pulse at the first end 208 of the waveguide 206 and the time of receiving the mechanical strain pulse by the piezoceramic element 212 at the second end 210 of the waveguide 206. In an embodiment, a timer may be used for monitoring the time lapse. Based on the monitored time lapse, the linear transducer 204 may generate the analog current output indicative of the position of the position magnet 202 may monitor the change in the position of the rotary drill head 114. In an exemplary embodiment, the analog current output may be within a range of about 4 mA to 20 mA.

In an aspect of the present disclosure, the analog current output of the linear transducer 204 may be further converted to an output indicating either the position of the rotary drill head 114 with respect to the mast 106 or track the change in the linear position of the drill bit 116. For example, the rotary drill head position measurement system 200 may be communicably coupled to the operator station of the blast hole drill machine 100 which may include a conversion module configured to convert the analog current output signal in mA units into a distance unit such as millimeter and/or centimeter or the like. As will be understood, the distance unit may indicate the change in the linear position of the drill bit 116 in the blast hole drill machine 100.

INDUSTRIAL APPLICABILITY

The industrial applicability of the system and method for determining a rotary drill head position of a blast hole drill machine described herein will be readily appreciated from the foregoing discussion. The rotary drill head position measurement system 200 uses a non-contacting type linear transducer 204. The non-contact of the linear transducer 204 eliminates the wear and provides durability and output repeatability. Additionally, the magnetostrictive position sensor of the linear transducer 204 determines the position of the position magnet 202 with precision and speed that does not need recalibration or rehoming after a power loss.

FIG. 3 illustrates an exemplary method flow chart 300 for determining position of the rotary drill head 114 in the blast hole drill machine 100. At step 302, the position magnet 202 is moved corresponding to the movement of the rotary drill head 114 in the blast hole drill machine 100. During the operation of the blast hole drill machine 100, the position magnet 202 moves with the feed cylinder 120 and in proportion to movement of the rotary drill head 114 along the mast 106 and generates the first magnetic field. Further, an electric current pulse is introduced at the first end 208 of the waveguide 206 within the mast 106. In an aspect of the present disclosure, the electric current pulse generates the second magnetic field across the waveguide 206.

At step 304, the strain pulse is detected using the waveguide 206 based on the position of the position magnet 202. In an aspect of the present disclosure, the piezoceramic element 212 is configured to detect the mechanical strain pulse at the second end of the waveguide 206. For example, the first magnetic field of the position magnet 202 and the second magnetic field of the waveguide 206 intersect with each other. The intersection of the first magnetic field and the second magnetic field may be configured to generate the mechanical strain pulse which travels at pre-determined speed towards the second end of the waveguide 206.

Furthermore, at step 306, a first output signal is generated based on the mechanical strain pulse, the first output signal output is indicative of the position of the position magnet 202 which is further indicative of the rotary drill head 114 position of the blast hole drill machine 100. In an aspect of the present disclosure, a time lapse between the introduction of the electric current pulse at the first end of the waveguide 206 and the receiving of the mechanical strain pulse at the second end of the waveguide 206 is determined. Based on the determined time lapse, the linear transducer 204 is configured to generate the electrical signal output in the form of analog current output to indicate the position of the position magnet 202 within the mast 106. In an embodiment, the analog current output of the linear transducer 204 is within a range of about 4 mA to 20 mA.

In an aspect of the present disclosure, the generated electrical signal out may be converted to a second output signal indicative of the change in the linear position of the drill bit 116 of the blast hole drill machine 100. For example, the generated electrical signal output may be communicated to the conversion module within the operator station of the blast hole drill machine 100. The conversion module may convert the determined position of the position magnet 202 into the distance or the change in the linear position of the drill bit 116.

While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof. 

What is claimed is:
 1. A blast hole drill machine comprising: a deck frame; a mast mounted on the deck frame; a feed cylinder supported on the mast and configured to move in proportion to movement of a rotary drill head along the mast; a position magnet moveably disposed on the feed cylinder; and a linear transducer extending along the mast and configured to detect a movement of the position magnet indicative of a change in a position of the rotary drill head.
 2. The blast hole drill machine of claim 1, wherein the feed cylinder is a dual rod, single piston type feed cylinder having a cylinder body.
 3. The blast hole drill machine of claim 2, wherein the position magnet is attached to the cylinder body.
 4. The blast hole drill machine of claim 1, wherein the linear transducer is a magnetostrictive position sensor.
 5. The blast hole drill machine of claim 4, wherein the magnetostrictive position sensor includes a magnetostrictive waveguide extending up to half a length of the mast.
 6. The blast hole drill machine of claim 5, wherein the magnetostrictive position sensor includes a piezoceramic element operatively coupled to the magnetostrictive waveguide.
 7. A rotary drill head position measurement system for a blast hole drill machine, the rotary drill head position measurement system comprising: a position magnet moveably disposed on a feed cylinder and configured to move with the feed cylinder and in proportion to movement of a rotary drill head along a mast of the blast hole drill machine; and a linear transducer extending along on the mast and configured to detect a movement of the position magnet indicative of a change in a position of the rotary drill head.
 8. The rotary drill head position measurement system of claim 7, wherein the position magnet is attached to a cylinder body of the feed cylinder.
 9. The rotary drill head position measurement system of claim 7 is configured to determine a change in a linear position of a drill bit of the blast hole drill machine based on the change in the position of the rotary drill head.
 10. The rotary drill head position measurement system of claim 7, wherein the linear transducer is a magnetostrictive position sensor.
 11. The rotary drill head position measurement system of claim 10, wherein the magnetostrictive position sensor includes a magnetostrictive waveguide extending up to half a length of the mast.
 12. The rotary drill head position measurement system of claim 11, wherein the magnetostrictive position sensor includes a piezoceramic element operatively coupled to the magnetostrictive waveguide.
 13. A method for determining a rotary drill head position in the blast hole drill machine, the method comprising: moving a position magnet corresponding to a movement of a rotary drill head of the blast hole drill machine; detecting a strain pulse using a magnetostrictive waveguide based on the movement of the position magnet; and generating an electrical signal based on the strain pulse indicative of a position of the position magnet.
 14. The method of claim 13 further comprises receiving an electrical excitation signal along a magnetostrictive waveguide extending up to half a length of a mast of the blast hole drill machine.
 15. The method of claim 14, wherein detecting the strain pulse comprises generating a first magnetic field by the position magnet.
 16. The method of claim 15, wherein detecting the strain pulse further comprises generating a second magnetic field by a magnetostrictive waveguide in response to the electrical excitation signal.
 17. The method of claim 16 further comprises generating the strain pulse in response to an intersection of the first magnetic field and the second magnetic field.
 18. The method of claim 17 further comprises generating a first output signal in response to receiving the strain pulse by using a piezoceramic element operatively coupled to the magnetostrictive waveguide, the first output signal indicative of a position of the position magnet.
 19. The method of claim 18 further comprises determining a time lapse between the electrical excitation signal and receiving of the strain pulse by using the piezoceramic element.
 20. The method of claim 19 further comprises generating a second output signal indicative of the change in the linear position of a drill bit 